Optical sensor for utility meter

ABSTRACT

A radio frequency automated meter reading (AMR) device for determining quantities of a consumed utility product including electric, gas and water service. The present invention intermittently transmits utility product consumption as a modulated RF signal, and does not require complex polling and bi-directional communication. Data is obtained and formatted for transmission and is adapted to be received by a remote receiving device having an RF receiver. The present invention is adaptable to water meters, gas meters and electric meters, and has an IR programming module facilitating remote programming and diagnostic procedures. In the case of water and gas meters, an internal lithium battery provides an operational life of up to ten years. In the case of the electric meter, power is tapped directly from the electric service.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation of and claims priority of co-pending U.S.patent application Ser. No. 09/419,743 entitled “Radio FrequencyAutomated Meter Reading Device” filed Oct.16, 1999, the teachings ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention is generally related to utility meterreading devices, and more particularly to automated devices utilized toremotely and efficiently obtain meter readings of utility metersproviding electric, gas and water service.

BACKGROUND OF THE INVENTION

[0003] Organizations which provide electric, gas and water service tousers are commonly referred to as “utilities”. Utilities determinecharges and hence billings to their customers by applying rates toquantities of the service that the customer uses during a predeterminedtime period, generally a month. This monthly usage is determined byreading the consumption meter located at the service point (usuallylocated at the point where the utility service line enters thecustomer's house, store or plant) at the beginning and ending of theusage month. The numerical difference between these meter readingsreveals the kilowatts of electricity, cubic feet of natural gas, or thegallons of water used during the month. Utilities correctly perceivethese meters as their “cash registers” and they spend a lot of time andmoney obtaining meter reading information.

[0004] An accepted method for obtaining these monthly readings entailsusing a person (meter reader) in the field who is equipped with a ruggedhand held computer, who visually reads the dial of the meter and entersthe meter reading into the hand held. This method, which is oftenreferred to as “electronic meter reading”, or EMR, was first introducedin 1981 and is used extensively today. While EMR products today arereliable and cost efficient compared to other methods where the meterreader records the meter readings on paper forms, they still necessitatea significant force of meter readers walking from meter to meter in thefield and physically reading the dial of each meter.

[0005] The objective of reducing the meter reading field force oreliminating it all together has given rise to the development of“automated meter reading”, or AMR products. The technologies currentlyemployed by numerous companies to obtain meter information are:

[0006] Radio frequency (RF)

[0007] Telephone

[0008] Coaxial cable

[0009] Power line carrier (“PLC”)

[0010] All AMR technologies employ a device attached to the meter,retrofitted inside the meter or built into/onto the meter. This deviceis commonly referred to in the meter reading industry as the MeterInterface Unit, or MIU. Many of the MIU's of these competing productsare transceivers which receive a “wake up” polling signal or a requestfor their meter information from a transceiver mounted in a passingvehicle or carried by the meter reader, known as a mobile datacollection unit (“MDCU”). The MIU then responsively broadcasts the meternumber, the meter reading, and other information to the MDCU. Afterobtaining all the meter information required, the meter reader attachesthe MDCU to a modem line or directly connects it to the utility'scomputer system to convey the meter information to a central billinglocation. Usually these “drive by” or “walk by” AMR products operateunder Part 15 of the FCC Rules, primarily because of the scarcity of, orthe expense of obtaining, licenses to the RF spectrum. While these typesof AMR systems do not eliminate the field force of meter readers, theydo increase the efficiency of their data collection effort and,consequentially, fewer meter readers are required to collect the data.

[0011] Some AMR systems which use RF eliminate the field force entirelyby using a network of RF devices that function in a cellular, or fixedpoint, fashion. That is, these fixed point systems use communicationconcentrators to collect, store and forward data to the utilities'central processing facility. While the communication link between theMIU and the concentrator is almost always either RF under Part 15 orPLC, the communication link between the concentrator and the centralprocessing facility can be telephone line, licensed RF, cable, fiberoptic, public carrier RF (CDPD, PCS) or LEO satellite RF. The advantageof using RF or PLC for the “last mile” of the communication network isthat it is not dependent on telephone lines and tariffs.

[0012] There is desired an improved meter reading device and methodologywhich improves upon the available AMR products through simplificationand ease of use.

SUMMARY OF THE INVENTION

[0013] The present invention achieves technical advantages as an AMRdevice and method of use which is adapted to couple to utility meters toobtain data including a measured quantity of delivered product, andfurther including control circuitry and a transmitter generating a datasignal indicative of the measured quantity at a particular RF frequencyand predetermined time interval, without requiring external polling. Thecontrol circuitry generates the data signal periodically at a firstpredetermined time interval which can be selectively programmed via aprogramming module by a separate programming or diagnostic device. Thepresent invention achieves technical advantages by not requiringexternal polling to obtain data, thereby simplifying the data collectionprocess by eliminating complicated data exchange protocols andsimplifying the equipment required (i.e. using a transmitter at the MIUinstead of a transceiver).

[0014] The present invention comprises a device having an interfacemodule adapted to couple to a utility meter measuring a quantity of adelivered product, the interface module providing a first signalindicative of the measured quantity. The device further comprises acontroller receiving the first signal and generating a data signalindicative of the measured quantity at a first predetermined timeinterval, without requiring external polling. A transmitter responsivelycoupled to the controller circuit modulates the data signal, andtransmits the modulated data signal at a predetermined RF frequency.Preferably, the controller formats the data signal into a data streamhaving a plurality of fields. A first field comprises data indicative ofthe measured quantity of delivered product, i.e. meter reading. Anothersecond field comprises data indicative of an identity of the measuringunit. The device is particularly adapted to obtain the measured quantityof delivered product comprising of electricity, natural gas and water,and can be adapted to other meters delivering product as well.

[0015] The present invention further comprises a programming modulefunctionally coupled to the controller and adapted to selectively adjustoperating parameters of the controller. The programming module isadapted to selectively adjust, for instance, the predetermined timeinterval between transmissions of the modulated data signal, forinstance, allowing the data to be selectively transmitted ever 10seconds, ever minute, once an hour, and so forth. The programming modulecomprises a transceiver adapted to provide data to a diagnostic andprogramming device indicative of operating characteristics of thedevice, including any changes of device performance, battery levels, andfurther allowing the reception of data such as to update of internalsoftware via downloading through the transceiver when desired. Theinterface module preferably comprises an optical sensor and opticaltransmitter, such as an Infrared (IR) transceiver.

[0016] According to a second embodiment of the present invention, thereis provided a method of transmitting a data signal comprising the stepsof sensing a utility meter measuring a quantity of a delivered product,and responsively generating a first signal indicative of the sensedmeasured quantity. The data signal is formatted and has a plurality offields, wherein a first field is indicative of the sensed measuredquantity of product. This formatted data signal is modulated andtransmitted as a modulated data signal at a predetermined RF frequency.This modulated data signal is preferably transmitted at a predeterminedtime interval, and advantageously does not require any external pollingsignal, complicated data exchange protocols, or complicated dataexchange algorithms. The method of the present invention furtherprovides the step of adjusting the format of the first signal using aprogramming device, wherein the programming device comprises an IRtransceiver. The measured product may comprise of water, electricity,gas, or other consumed product of a household.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a perspective view of a data transmitting moduleaccording to the present invention adapted to a household electricmeter;

[0018]FIG. 2 is a perspective view of a data transmitting deviceaccording to a second embodiment of the present invention adapted to befastened onto a water meter pit lid and adapted to read a water meter;

[0019]FIG. 3 is a electrical block diagram of an electric meter unitaccording to the first embodiment of the present invention;

[0020]FIG. 4 is an electrical block diagram of a water meter unitaccording to a second embodiment of the present invention;

[0021]FIG. 5 is a signal timing diagram of the optical sensor unit forthe electric meter of FIG. 3;

[0022]FIG. 6 is a signal timing diagram of the optical sensor of thewater meter unit of FIG. 4;

[0023]FIG. 7 is a byte data format diagram for the water and electricmeter units;

[0024]FIG. 8 is a timing diagram of an initiated wake-up sequence by aremote programming device;

[0025]FIG. 9 is a timing diagram of a command/response sequence of thecontroller to the remote programming device;

[0026]FIG. 10 is a timing diagram of a sleep command being provided tothe controller;

[0027]FIG. 11 is a sleep timing diagram of sequence;

[0028]FIG. 12 is a timing diagram of an oscillator of the water meterunit;

[0029]FIG. 13 is a timing diagram of the controller communicating withthe EE PROM of the water and electric units;

[0030]FIG. 14 is a timing diagram of the controller of the water unitmeasuring interval battery voltages;

[0031]FIG. 15 is a full electrical schematic of the electric meter unitaccording to the first preferred embodiment of the present invention;

[0032]FIG. 16 is a full electrical schematic of the water meter unitaccording to the second embodiment of the present invention; and

[0033]FIG. 17 is a full schematic diagram of a receiver adapted toreceive and process modulated data signals from the data transmittingdevices according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034] Referring now to FIG. 1, there is illustrated a householdelectric meter unit generally shown at 10 having adapted therewith anelectric meter reading unit 12 according to a first preferred embodimentof the present invention coupled to sense a black spot 13 on therotating meter disk generally shown at 14. Electric meter unit 12 has anoptical sensor for detecting the passing of the back spot 13 therepastto ascertain the consumed amount of electricity correlated to the readout of the visual display 15 of meter unit 10.

[0035]FIG. 2 is the perspective view of a water meter unit according toa second preferred embodiment of the present invention generally beingshown at 16. The circular structure 18 on the top of device 16 isadapted to fasten the unit 16 onto a water meter pit lid (not shown)with an antenna node (not shown) sticking up through a hold drilledthrough the pit lid.

[0036] Referring now to FIG. 3, there is illustrated an electrical blockdiagram of the electric meter unit 12 according to the first embodimentof the present invention. Electric meter unit 12 is seen to include acontroller 20, which may comprise of a microcontroller, a digital signalprocessor (DSP) or other suitable controlling device, preferably being aprogrammable integrated circuit having suitable software proramming.Device 12 is further seen to include an infrared (IR) optical sensor 22adapted to sense the passing of the black spot 13 of the metered disk 14of electric meter unit 10. Optical sensor 22 preferably operates bygenerating pulses of light using a light emitting diode, and sensing thereflection of light from the meter disk 14, and determining the passingof the black spot 13 by sensing a reduced reflection of the impinginglight therefrom.

[0037] Electric meter unit 12 is further seen to include a memory devicecomprising an EE PROM 28 storing operating parameters and controlinformation for use by controller 20. An AC sense module 30 is alsocoupled to controller 20 and senses the presence of AC power 33 beingprovided to the meter unit 10 via an AC interface 32.

[0038] A radio frequency (RF) transmitter 36 is coupled to andcontrolled by controller 20, and modulates a formatted data signalprovided thereto on line 38. RF transmitter 36 modulates the formatteddata signal provided thereto, preferably transmitting the modulatedsignal at a frequency of about 916.5 MHz at 9600 bits per second (BPS),although other frequencies or data rates are suitable and limitation tothis frequency or baud rate is not to be inferred.

[0039] A programming optical port 40 is provided and coupled tocontroller 20 which permits communication between controller 20 and anexternal optical infrared device 42 used for programming controller 20,and for selectively diagnosing the operation of electric meter unit 12via the optical port 40. Optical port 40 has an IR transceiver adaptedto transmit and receive infrared signals to and from the external device42 when the external device 42 is disposed proximate the optical port 40for communication therewith. Device 42 asynchronously communicates withcontroller in a bi-directional manner via port 40, preferably at 19,200baud.

[0040] Optical sensor 22 communicates via a plurality of signals withcontroller 20. Optical sensor 22 provides analog voltages indicative ofand corresponding to the sensed black spot of disk 24 via a pair of datalines 50 and 52 which interface with an analog to digital controller(ADC) 54 forming a sub-portion of controller 20.

[0041] Referring now to FIG. 4, there is generally shown detailedelectrical block diagram of the water meter unit 16 according to thesecond preferred embodiment of the present invention, wherein likenumerals refer to like elements to those shown in FIG. 3. The watermeter unit 16 is substantially similar to the electric meter unit 12 infunction, but having some differences necessary for operation with ahousehold water meter unit. Specifically, water meter unit 16 has anoptical sensor 60 adapted to be positioned proximate a water meter face62 having a needle 64, which needle 64 indicates a consumed amount ofwater communicated through the water meter unit. Optical sensor 60senses the position of needle 64 via infrared (IR) sensing electronics,and provides the sensed position of needle 64 via communication link 66to an optical sensor interface 68. The sensed position of needle 64 isprovided as a data signal comprising an analog voltage transmitted online 70 to an ADC 72 of controller 20. In this embodiment, water meterunit 16 is provided with an internal battery 80 powering themicrocontroller 20 and other circuitry, preferably being a lithiumbattery operating at about 3.6 volts. A battery voltage measuring unit82 senses and measures the current operating voltage of battery 80, andoutputs an analog voltage signal indicative thereof on line 84 to an ADC86 of microcontroller 20. The value of the analog voltage signal on line84 is a function of the battery voltage of battery 80 and is about 1.2volts when battery 80 is providng 3.6 volts. The value of the BatteryVoltage Measuring circuit is about 1.2V, but the perceived value by theADC is a function of the ADC Ref voltage, which is the battery voltage.For example, if the ADC measures the 1.2V and it was 33% full scale ofthe ref voltage (battery voltage), then the battery voltage would be:

1.2×1/0.33=3.6V

[0042] The 1.2V is constant over a wide battery voltage range.

[0043] A low power oscillator 90 operating at about 32 kHz generates a 4Hz logic interrupt signal to controller 20, which controls the speed ofcontroller 20. By providing only a 4 Hz interrupt signal,microcontroller 20 operates at a very slow speed, and thus consumes verylittle power allowing water meter unit 16 to operate at up to about 10years without requiring replacement of lithium battery 80.

[0044] The EE PROM 28 is selectively enabled by the microcontroller 20via an enable line 96, and once enabled, communication between themicrocontroller 20 and the EE PROM 28 follows an IIC protocol. Likewise,the battery voltage measuring device 82 is selectively enabled poweredby the microcontroller 20 via a control line 98 such that the batteryvoltage is sensed only periodically by the controller 20 to conservepower.

[0045] The optical sensor 60 is controlled by controller 20 via opticalsensor interface 68 to determine the water position and presence ofmeter needle 64. The sensor 60 is attached to the lens of the watermeter (not shown). An infrared (IR) signal 100 is periodicallytransmitted from the sensor 60, and the reflection of the IR signal ismeasured by the sensor 60 to determine the passage of needle 64. Thesensor 60 operates in cyclic nature where the sensing is performed every250 milliseconds. The intensity of the IR signal transmitted by sensor60 is controlled by two drivelines on control line 66 from themicro-controller 20. The IR intensity is set according to the opticalcharacteristics of the water meter face. The sensor 60 emits an intense,but short burst of IR light. The IR receiver 68 responsively generatesan analog voltage on signal line 70 which voltage is a function of thereceived IR light intensity from optical sensor 60. This voltage isconnected directly to the ADC 72 of the controller 20. The controller 20measures this converted (digital) signal, and uses the value in analgorithm that ascertains the value over time to determine if the watermeter needle has passed under the sensor 60. The algorithm alsocompensates for the effects of stray light. The mechanical shape of thesensor 60 and orientation of the IR devices, such as light emittingdiodes, determines the optical performance of the sensor and itsimmunity to stray IR light.

[0046] The water meter unit 16 periodically transmits a modulatedformatted data signal on an RF link 110 that is preferably tuned at916.5 MHz with on-off-keyed data at 9600 bits per second (9600 baud).The transmitter 36 transmits the data in formatted packets or messages,as will be discussed shortly. These formatted messages are transmittedat a repetition rate that has been initialized into the unit 16, andwhich may be selectively set between every one second and up tointervals of every 18 hours, and which may be changed via the opticalport 40 by the programminge external optical device 42. The formattedmessages modulated by the transmitter 36, as will be discussed shortly,contain fields including an opening flag, message length, system number,message type, data, check sum and closing flag, as will be discussedshortly in reference to FIG. 7. The messages are variable length,whereby the message length field indicates how long the message is. Themessage type field indicates how to parse or decode the data field.Different messages carry and combine different data items. Data itemsinclude network ID, cumulative meter reading, clock time, batteryvoltage, sensor tamper, sensor diagnostic, and trickle flags.

[0047] As previously mentioned, low power 32 kHz oscillator 90 generatesa 4 Hz square wave output. This signal is connected to the controller 20which causes an interrupt ever 250 milliseconds. The micro-controlleruses this interrupt for clock and timing functions. In normal mode, themicrocontroller is asleep and wakes up every 200 milliseconds andperforms a scheduling task for about 50 milliseconds. If a task isscheduled to execute, it will execute that task and return to sleep. Innormal mode, all tasks are executed within the 250 millisecond window.

[0048] In the case of the optical sensor 22 of FIG. 3, the sensor 22 isattached to the electric meter such that the sensor faces the metereddisk surface. The IR signal is periodically transmitted from the sensorand the reflection is measured. As the black spot passes under thesensor, a variation in the reflected IR signal occurs. The sensoroperates in cyclic nature where the sensing is performed every 33milliseconds. The IR receiver of sensor 22 generates analog voltages onlines 50 and 52 that is a function of the received IR light intensityand are connected to the ADC 72 in the microcontroller 20. Thecontroller 20 measures this converted (digitized) voltage, and used thevalue in the algorithm. The algorithm senses the values over time todetermine if the black spot has passed under the sensor. To detectreverse rotation of the metered disk, the sensor 22 has two sensors, asshown. The controller 22, with its algorithm, determines the directionof disk rotation as the black spot passes the sensor 22. The black spotis a decal and does not reflect IR light. This is determined by thedecal's material, color and surface texture. As with the water meter,the algorithm and sensor shrouding compensate for the effects of straylight.

[0049] The AC line interface 32 interfaces to the AC line coupled to theelectric meter through a resistive tap. The resistors limit the currentdraw from the AC line to the electric meter unit 12. The AC is thenrectified and regulated to power the unit 12. The AC sensor 30 detectsthe presence of AC voltage on the AC line 33. The sensed AC is rectifiedand a pulse is generated by sensor 30. This pulse is provided to themicro-controller 20 where it is processed to determine the presence ofadequate AC power.

[0050] Referring now to FIG. 5, there is shown a waveform diagram of thesignals exchanged between the optical sensor 22 and the controller 20 ofthe electric meter unit 12 shown in FIG. 3. The logic signals generatedby controller 20 control the optical sensor 22 to responsively generatean IR signal and sense a refracted IR signal from the metered disk 24.It can be seen that the reflected 0.3 millisecond IR signal is acquiredwithin 1.3 milliseconds after enabling for sensing by ADC 54 andprocessed by controller 20. Preferably, this measuring sequence isperformed every 33 milliseconds, which periodic rate can be programmedvia optical port 40 if desired.

[0051] Referring now to FIG. 6, there is shown the timing diagram of thesignals between optical sensor 68 and controller 20 for water meter unit16 of FIG. 4. The logic of the driving signals is shown below inTable 1. TABLE 1 Net Sensor Drive Drive 1 Drive 2 High 0 0 Medium 0 1Low 1 0

[0052] As shown in the timing diagram of FIG. 6, the analog signalprovided on line 70 by optical sensor 68 rises to an accurate readablevoltage in about 140 milliseconds, and has a signal width of about 270milliseconds. The period of the analog voltage is about 250milliseconds, corresponding to a signal acquisition rate of 4 Hzcorresponding to the timing frequency provided on line 92 to controller20.

[0053] Referring now to FIG. 7, there is shown the message format of thedata signal provided by controller 20 on output line 38 to RFtransmitter 36. The message is generally shown at 120 and is seen tohave several fields including:

[0054] opening flag (OF) comprised of two bytes;

[0055] message length (ML) having a length of one byte;

[0056] system number (SN) having a length of one byte;

[0057] message type (MT) one byte;

[0058] data, which length is identified by the message length parameter(ML);

[0059] check sum (CSUM) two bytes; and

[0060] closing flag (CF) one byte.

[0061] Further seen is the data format of one byte of data having onestart bit and 8 bits of data non-returned to zero (NRZ) and onestop-bit. The length of each byte is preferably 1.04 milliseconds inlength.

[0062] Referring now to FIG. 8, there is illustrated the message formatand timing sequence of messages generated between the external opticaltiming device 42 and microcontroller 20 via optical port 40. As shown inFIG. 8, a plurality of synchronization bytes are provided by device 42on the receive data (RXD) line to controller 20, and upon therecognition of the several bytes by controller 20, the controller 20generates a response message to the wake-up message on the transmit data(TXD) line via optical port 40 to the external device 42. Thereafter,shown in FIG. 9, a command data message may be provided by the externaldevice 42 to controller 20 on receive data line RXD, with response data,if required, being responsively returned on the transmit data line TXDto device 42 if required by the command.

[0063] As shown in FIG. 10, a sleep command is then generated byexternal device 42 upon which no response by controller 20 is generatedand the unit 12 goes to sleep. As shown in FIG. 11, after a command hasbeen sent to controller 20, and responded to, the unit 12 will time outafter a predetermined period of time if no other commands are received,such as 120 seconds, with a message being sent by controller 20 ontransmit line TXD indicating to the external device 42 that the unit 12has gone to sleep.

[0064] The message sequence shown in FIGS. 8-11 applies equally to boththe electric unit 12 and the water unit 16. Referring now to FIG. 12,there is illustrated the 4 Hz square wave interrupt signal generated bythe low power oscillator 90 to the microcontroller 20.

[0065] Referring to FIG. 13, there is illustrated the timing ofcommunications between the EE PROM 28 and the controller 20, whereby theEE PROM is enabled by a logic one signal on line 96, with bi-directionaldata being transferred using an IIC link on lines SCL, and lines SDA.This applies to both the water unit 16 and the electric unit 12.

[0066] Referring to FIG. 14, there is illustrated the timing diagram forsensing the internal battery voltage in the water meter unit 16 shown inFIG. 4. A logic high signal is generated on enable line 98 by controller20, whereby the battery measuring unit 82 responsively senses thebattery voltage via line 130 from DC battery 80. Battery measuring unit82 responsively provides an analog voltage signal on line 84 indicativeof the voltage of battery 80 to the ADC 86 of controller 20. The analogvoltage provided on signal line 84 is approximately 1.2 volts when thebattery 80 is at full strength, being about 3.6 volts.

[0067] Referring now to FIG. 15, there is illustrated a detailedschematic diagram of the electric meter unit 12, wherein like numeralsshown in FIG. 3 refer to like elements.

[0068] Referring now to FIG. 16 there is illustrated a detailedschematic diagram of the water meter unit 16, shown in FIG. 4, whereinlike numerals refer to like elements.

[0069] Referring now to FIG. 17, there is illustrated a detailedschematic diagram of an external receiver unit adapted to receive andintelligently decode the modulated formatted data signals provided on RFcarrier 110 by the RF transmitter 36. This receiver 140 both demodulatesthe RF carrier, preferably operating at 916.5 MHz, at 9600 baud, anddecodes the demodulated signal to ascertain the data in the fields ofmessage 120 shown in FIG. 7. This receiver unit 140 has memory forrecording all data collected from the particular sensored units beingmonitored by a field operator driving or walking in close proximity tothe particular measuring unit, whether it be a water meter, gas meter orelectric meter, depending on the particular meter being sensed andsampled. All this data is later downloaded into remote computers forultimate billing to the customers, by RF carrier or other communicationmeans.

[0070] In a preferred embodiment, the RF carrier 110 is generated atabout 1 milliwatt, allowing for receiver 140 to ascertain the modulateddata signal at a range of about 1,000 feet depending on RF path loss.The RF transmitters 36 are low power transmitters operating inmicroburst fashion operating under part 15 of the FCC rules. Thereceiver 140 does not have transmitting capabilities. The receiver ispreferably coupled to a hand held computer (not shown) carried by theutility meter reader who is walking or driving by the meter location.

[0071] In the case of the electric meter unit 12, the device obtainselectrical power to operate from the utility side of the power line tothe meter and is installed within the glass globe of the meter. The maincircuit board of this device doubles as a mounting bracket and containsa number of predrilled holes to accommodate screws to attach to variousthreaded bosses present in most electric meters.

[0072] In the case of the water meter, electric power is derived fromthe internal lithium battery. The water meter unit 12 resides under thepit lid of the water meter unit, whereby the antenna 142 is adapted tostick out the top of the pit lid through a pit lid opening to facilitateeffective RF transmission of the RF signal to the remote receiver 140.

[0073] The present invention derives technical advantages bytransmitting meter unit information without requiring elaborate pollingmethodology employed in conventional mobile data collection units. Themeter units can be programmed when installed on the meter device, in thecase of the water and gas meters, or when installed in the electricmeter. The external programming diagnostic device 42 can communicatewith the optical port 40 of the units via infrared technology, and thuseliminates a mechanical connection that would be difficult to keep cleanin an outdoor environment. Also, the optical port 40 of the presentinvention is not subject to wear and tear like a mechanical connection,and allows communication through the glass globe of an electric meterwithout having to remove the meter or disassemble it. In the case of theelectric meter, the present invention eliminates a potential leakagepoint in the electric meter unit and therefore allows a more watertightenclosure.

[0074] The transmitting meter units of the present invention can beprogrammed by the utility to transmit at predetermined intervals,determined and selected to be once ever second to up to several hoursbetween transmissions. Each unit has memory 28 to accommodate thestorage of usage profile data, which is defined as a collection of meterreadings at selected intervals. For example, the unit can be programmedto gather interval meter readings ever hour. If the unit is set torecord interval readings every hour, the memory 28 may hold the mostrecent 72 days worth of interval data. This interval data constitutesthe usage profile for that service point. Typically, the utility usesthis information to answer customer complaints about billings andreading and as a basis for load research studies.

[0075] The profile intervals are set independently of the transmittinginterval and the device does not broadcast the interval data. The onlyway this interval data can be retrieved by the utility is to attach theprogramming unit 42 to the meter unit of the present invention anddownload the file to a handheld or laptop computer. With the programmingunit 42, one can determine the status of the battery on the water meterwhich is including in the profile data.

[0076] The present invention allows one to selectively set thetransmission intervals thereby controlling the battery life. The longerthe interval, the longer the battery life. In the case of electric meterunit, power is derived directly from the utility side of the electricservice to the meter. The battery on the water meter unit is notintended to be field replaceable. In order to control cost, the watermeter product is designed to be as simple as possible with the watermeter unit enclosure being factory sealed to preserve the watertightintegrity of the device. Preferably, a D size lithium cell is provided,and the unit is set to transmit once every second, providing a batterylife of about 10 years. The water meter unit of the present inventioncan be fitted to virtually any water meter in the field and the utilitycan reap the benefits of the present invention without having topurchase a competitor's proprietary encoder and software. In the case ofexisting water meters that incorporate an encoder which senses therotation of the water meter, these encoders incorporate wire attachmentspoints that allow attachments to the manufactures proprietary AMRdevice. The present invention derives advantages whereby the sensor 60of the present invention can be eliminated, with the sensor cable 66being coupled directly to the terminals on the encoder of this type ofdevice.

[0077] Though the invention has been described with respect to aspecific preferred embodiment, many variations and modifications willbecome apparent to those skilled in the art upon reading the presentapplication. It is therefore the intention that the appended claims beinterpreted as broadly as possible in view of the prior art to includeall such variations and modifications.

We claim
 1. An interface module, comprising: a) a transmitter adapted toemit radiation toward a face of a meter measuring a quantity ofdelivered product; b) a receiver adapted to detect radiation reflectedfrom said meter; and c) a circuit converting the intensity of saiddetected radiation into an output signal indicative of the quantity ofdelivered product.
 2. The interface module specified in claim 1 whereinsaid transmitter emits and said receiver detects electromagneticradiation.
 3. The interface module specified in claim 2 wherein saidtransmitter emits and said receiver detects infrared radiation.
 4. Theinterface module specified in claim 2 wherein said transmitter emits andsaid receiver detects visible light.
 5. The interface module specifiedin claim 2 wherein said transmitter emits and said receiver detectsultraviolet radiation.
 6. The interface module specified in claim 2wherein said receiver is a photodetector.
 7. The interface modulespecified in claim 6 wherein said photodetector has a photoconductiveregion comprising cadmium sulfide.
 8. The interface module specified inclaim 6 wherein said photodetector has a photoconductive regioncomprising cadmium selenide.
 9. The interface module specified in claim1 wherein said transmitter emits bursts of radiation over apredetermined interval of time, and said receiver detects the reflectedradiation over said predetermined interval of time.
 10. The interfacemodule specified in claim 9 wherein the interface module is adapted tointerface with a meter having a needle, wherein said receiver outputspredetermined values, one value corresponding to the intensity ofradiation being reflected by the needle coupled to said meter, saidneedle contrasting with said meter's surface, and a different valuecorresponding to the intensity of said emitted radiation being reflectedby said meter's surface.
 11. The interface module specified in claim 10wherein said outputted values are voltage levels.
 12. The interfacemodule specified in claim 1 wherein the receiver outputs a signalcorresponding to radiation reflected by one or more markings on saidmeter during a predetermined interval of time.
 13. The interface modulespecified in claim 12 wherein the outputted values are voltage levels.14. The interface module specified in claim 1 wherein the intensity ofsaid emitted radiation is controllable based on translucentcharacteristics of said meter's face.
 15. The interface module specifiedin claim 6 wherein the active region of the photodetector comprises aphoto conductive surface.
 16. The interface module specified in claim 6wherein the active region of the photodetector comprises a photovoltaicsurface.
 17. The interface module specified in claim 6 wherein thephotodetector comprises a photodiode.
 18. The interface module specifiedin claim 6 wherein the photodetector comprises a phototransistor. 19.The interface module specified in claim 1 wherein the receiver is aphotoemissive detector.
 20. The interface module specified in claim 2wherein the transmitter is an He—Ne laser.
 21. A method for sensing theposition of an indicator on a meter measuring a quantity of deliveredproduct, comprising the steps of: a) emitting radiation toward the faceof said meter; b) detecting the variations in intensity of the reflectedradiation; and c) converting the variations in intensity of saidreflected radiation into an output signal.
 22. The method of claim 21,further comprising the steps of: a) emitting said radiation over apredetermined interval of time; b) detecting the variations in intensityof said reflected radiation during said predetermined interval of time;and c) converting the variations in intensity of said reflectedradiation during the predetermined interval of time into time varyingsignal.
 23. The method of claim 21, further comprising the steps of: a)measuring the intensity of said reflected radiation over the face ofsaid meter during an instant in time; and b) correlating the locationsof different intensity levels to specific levels.